As far as detonating shells are concerned, the main effect of which on the target is achieved through splinter, it has been known for a long time that the effect on the target depends directly upon how close to the target the detonation takes place, and also whether this takes place above the target, which clearly produces the best effect, or on ground impact beside the target. Even though efforts are, of course, made to achieve direct strikes on the target, such direct strikes are not particularly frequent in spite of modern fire-control and missile-trajectory calculating instruments.
One way of bringing about air bursts directly above: the target aimed at is based on providing the shells with a programmable time fuse function which can be programmed for detonation at the trajectory distance from the firing point at which it is calculated that the target is situated. When using shells of this type it is desirable to carry out this programming as late as possible before firing. This is particularly the case with shell-firing infantry weapons where, with mobile positions, it may be expected that both oneself and the target are continuously moving around on the battlefield. Under these circumstances, it would therefore be a clear advantage if the time fuse function of the shells could be programmed as late as possible before firing, e.g. when the shell is ready for firing in the cartridge chamber of the shell-firing weapon.
Arranging such programming of the time fuse function of the shells inside the cartridge chamber of the weapon, however, involves certain problems because the cartridge chamber constitutes part of the barrel. However, it is heretofore known, however, that it is possible to program in an inductive manner electronic shell fuses which are designed in a special manner.
Since all shell-firing weapons, except possibly those of one-shot type, have barrels made of steel which are both electrically conductive and magnetic, inductive fuse programming was previously only possible before loading of the weapon or alternatively while the shell was being fed from a magazine to the cartridge chamber of the weapon. Furthermore, EP-A1-0300255 and EP-A1-0467055 describe proposals for how the same type of inductive programming can be carried out immediately after the shell has left the barrel. In these arrangements, it is proposed that the coil which is to supply the programming signal be placed immediately outside the mouth of the barrel so that the shell passes through it. For various reasons, these solutions have proved to be more difficult to implement in practice than was originally theoretically assumed. Then, as far as programming further away from the firing point is concerned, along the actual missile trajectory, this involves such great technical complications that, although they are by no means insurmountable, they would probably only be justified in terms of effectiveness in larger calibers such as 10.5 cm and above.